1. Technical Field
Illustrative embodiments of this disclosure relate to an image forming apparatus employing a reciprocally movable carriage with an image forming unit mounted thereon.
2. Description of the Background
An image forming apparatus is an apparatus used as a printer, a facsimile machine, a copier, a plotter, or a multi-functional peripheral (MFP) having several of the foregoing capabilities. One known conventional image forming apparatus employing a liquid-ejection recording method is an inkjet recording apparatus, which ejects liquid droplets from a recording head onto a recording sheet to form a desired image.
Inkjet-type image forming apparatuses fall into two main types: a serial-type image forming apparatus that forms an image by ejecting droplets while moving a recording head in a main scan direction, and a line-head-type image forming apparatus that forms an image by ejecting droplets from a recording head fixedly disposed in the image forming apparatus.
One conventional serial-type image forming apparatus has a carriage on which a liquid ejection head serving as an image forming unit is mounted. To form an image, the apparatus ejects droplets from the liquid ejection head while moving the liquid ejection head in the main scan direction to scan a sheet and intermittingly shifting the sheet in a sub-scanning direction perpendicular to the main scan direction.
However, in the conventional serial-type image forming apparatus, as the carriage reciprocally moves back and forth, the image forming apparatus vibrates. In particular, when the carriage speed is increased to enhance the print speed, the acceleration and deceleration speeds in the main scanning of the carriage are also increased, causing further vibration of the image forming apparatus. Alternatively, in a MFP including an image reading apparatus (also typically known as a scanner), such vibration at the printer side may be transmitted to the scanner during scanning, thereby degrading a resultant scanned image.
In light of the above-described situation, several techniques have been proposed to reduce or suppress vibration of the carriage. In one conventional technique, a vibration absorption member is provided between a carriage driving unit and the apparatus body frame to reduce the transmission of vibration, which is caused by reciprocal movement of a carriage, to the body frame.
In another conventional technique, the strength of impact against a body of a printer is detected, and an adjustable vibration absorption means of a printer-supporting unit is controlled in response to the detected impact.
In such a serial-type image forming apparatus, when an image is formed by ejecting droplets from the recording head while reciprocally moving the carriage back and forth, it is preferable that a guide member (carriage-support member) movably supporting the carriage is fixedly held by the body frame of the image forming apparatus with relatively high rigidity to reduce vibration of the carriage and enhance the accuracy of landing positions of the droplets on the recording medium sheet.
However, as with the above-described conventional serial-type image forming apparatus, when the carriage driving unit is mounted on the body frame via, for example, a rubber member serving as a vibration absorption member, the carriage is constantly held by a vibrating member such as the rubber member, thus degrading image quality.
Alternatively, the above-described technique in which the vibration absorption means of the printer support unit is adjusted in response to a detected impact may result in a relatively complicated configuration, posing production and cost challenges.